Drugs are commonly administered to patients via injections. Many patients associate injections with pain. A number of different methods are used to reduce the pain associated with an injection, for example, applying a topical anesthetic and/or ice to the injection site before the injection procedure.
U.S. Pat. No. 6,743,211 to Prausnitz at al., relevant portions of which are incorporated herein by reference, describes microneedle devices and methods of use thereof for the transport of molecules, including drugs and biological molecules, across tissue by improving the interaction of microneedles and a deformable, elastic biological barrier, such as human skin. The devices and methods are described as acting to (1) limit the elasticity, (2) adapt to the elasticity, (3) utilize alternate ways of creating the holes for the microneedles to penetrate the biological barrier, other than the simply direct pressure of the microneedle substrate to the barrier surface, or (4) any combination of these methods. Embodiments are described for limiting the elasticity of skin. The microneedle device includes features suitable for stretching, pulling, or pinching the skin to present a more rigid, less deformable, surface in the area to which the microneedles are applied (i.e. penetrate). Embodiments are described for adapting the device to the elasticity of skin, the device comprising one or more extensions interposed between the substrate and the base end of at least a portion of the microneedles.
An embodiment of the '211 patent is described in which the microneedle device includes jaws, typically one or more pairs, which can be pressed against the skin surface and triggered to close against a segment of skin. The size of the jaw opening is described as being selected based on the area of skin to be pinched to facilitate penetration of the microneedle array selected for use.
U.S. Pat. No. 5,478,315 to Brothers at al., relevant portions of which are incorporated herein by reference, describes a local anesthetic injection system for use with smaller children for providing an essentially pain free injection of a local anesthetic into a child's epidermis skin layer, above nerve endings, to deaden that skin area to receive en injection of a medicine through that deadened area utilizing a conventional hypodermic needle. The several embodiments of the system are described as including a body that has a cup arrangement with a flat edge upstanding well and is open thereacross. The cup is arranged to receive a force applied to the top thereof to urge the cup flat edge into the surface of a section of skin whereon the cup rests, causing the skin within the cup to be formed into a dome shape. A small hollow needle is maintained within the cup such that an open bevel needle end extends at an angle just below the plane of the cup edge. Thereby, as the dome of skin is formed within the cup, the needle bevel end is described as tending to travel into the dome of skin, above the skin nerve endings, allowing a vessel connecting to the needle to dispense a local anesthetic through the hollow needle bevel end when an operator applies a pressure generating force thereto.
U.S. Pat. No. 4,403,987 to Gottinger, relevant portions of which are incorporated herein by reference, describes an injection aid for supporting a hypodermic syringe and for facilitating injection of the needle of the syringe into a limb. The apparatus includes a syringe supporting member and a pair of guide rods for supporting the syringe supporting member for slideable movement between a first position wherein a needle supported by the syringe supporting member is retracted from the limb and an injecting position. A pair of spaced apart generally parallel support rods are also provided. The rearward ends of the support rods are adapted to rest on the limb and are integrally joined to the guide rods and are for supporting the guide rods. The support rods include forward ends for pinching flesh therebetween to cause the flesh adjacent the syringe needle to pucker.
U.S. Pat. No. 7,291,159 to Schmelzeisen-Redeker, relevant portions of which are incorporated herein by reference, describes a system for withdrawing body fluid from a body part in particular the finger pad, comprising a compression unit that is deformed when the body part is pressed against it and increases the internal pressure in a region of the body part, and a withdrawal device. Deformation of the compression unit is described as partially converting the primary pressing movement into a secondary movement which leads to an increase in the internal pressure in a region of the body part. A system for stimulating the outflow of body fluid using a deformable compression unit is also described.
US Patent Application Publication 2006/0293722 to Slatkine, relevant portions of which are incorporated herein by reference, describes apparatus adapted to inhibit pain signals generated by pain receptors in the skin during a skin related medical treatment such as an injection. An evacuation chamber is provided with an essentially rigid interface element larger than a threshold surface area through which a medical treatment can be administered to a selected skin region, one or more walls which are placeable in the vicinity of the skin region, an interior defined by the walls and by the interface element, and an opening at the bottom of the interior which is sealable by the skin region. A device is described as generating a vacuum within the evacuation chamber interior to a level greater than the threshold vacuum level suitable for drawing the skin region through the opening towards, and in a compressing relation against, the interface element, to inhibit the transmission of a pain signal generated by pain receptors located within the skin region.
The following patents and patent applications, relevant portions of which are incorporated herein by reference, may be of interest:    PCT Publication WO 06/069380 to Nguyen    U.S. Pat. No. 5,766,186 to Faraz    U.S. Pat. No. 5,662,678 to Macklin    U.S. Pat. No. 4,195,636 to Behnke    U.S. Pat. No. 6,200,296 to Dibiasi et al.,    US Patent Application Publication 2005/0033234 to Sadowski et al.    U.S. Pat. No. 5,190,521 to Hubbard et al.    U.S. Pat. No. 7,060,054 to Nissels